1. Field of the Invention
The invention relates to a moving-target-indicator (MTI) radar system in which the cancellation notch is broadened to include a selected range of target velocities. More specifically, the invention utilizes a non-coherent, non-doppler, MTI radar system containing apparatus for generating multiple MTI responses having cancellation notches at different target velocities and multiplying the responses together to obtain a broadened cancellation notch.
2. DESCRIPTION OF THE PRIOR ART
In an MTI radar system, normally, targets at zero velocity are detected and excluded. It would be desirable to exclude not only those at zero velocity but also those within a range of velocities for example from 0-60 kts (i.e., broaden the cancellation notch). This would allow for elimination of slow-moving targets such as rain squalls etc.
In the prior art, all MTI systems utilized coherent doppler radar for which no satisfactory method has been found for a broadening the cancellation notch. Additionally, non-coherent, non-doppler radar systems could not be used for MTI; hence the problem of broadening the cancellation notch never arose. Non-coherent, non-doppler systems could not be used for MTI because these systems were constrained to use long pulses which prevented MTI operation. The subtraction of the long pulses during MTI operation resulted in a difference that was too insignificant to be detected. Recently, technological advances have made possible transmitters and receivers with short pulses (nsec) having high power.